de Oliveira Lima Filho E, Malvestiti I. Mechanochemical Thiocyanation of Aryl Compounds
via C-H Functionalization.
ACS OMEGA 2020;
5:33329-33339. [PMID:
33403295 PMCID:
PMC7774286 DOI:
10.1021/acsomega.0c05131]
[Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Aryl thiocyanate compounds are important building blocks for the synthesis of bioactive compounds and intermediates for several functional groups. Reported thiocyanation reactions via C-H functionalization have limited substrate scope and low RME. The ball-milling method reported here uses ammonium persulfate and ammonium thiocyanate as reagents and silica as a grinding auxiliary. It afforded aryl thiocyanates with moderate to excellent yields for a wide variety of aryl compounds (36 examples, 8-96% yield), such as anilines, phenols, anisoles, thioanisole, and indole, thus tolerating substrates with sensitive functional groups. New products such as benzo[d][1,3]oxathiol-2-ones were obtained with C-4 substituted phenols. Thus, to our knowledge, we report, for the first time, aryl thiocyanation reaction by ball-milling at room temperature and solvent-free conditions, with short reaction times and no workup. Analysis of several mass-based green metrics indicates that it is an efficient greener method.
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